Reversible knife for loom dobbies



Dec. 28,1926. 1,612,082 I W. H. WAKEFIELD REVERSIBLE KNIFE FOR LOOM DOBBIES Filed May 27, 1926 Patented Dec. 28, 1926 h... WM-

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REVER$1BLE KNIFE Application filed May 2?,

This invention relates to in'rprovements in reversible knives for loom (lobbies and it is the principal object of the invention to provide such a knife with the requisite cross section to give sufi icicnt strength, and at the same time to construct the same so as to re duce to aminimum any tendency to rotate on the axis of the gudgeons while raising the harnesses.

Loom do'bbies usually employ upper and lower sets of hooks connected together in pairs, each pair being associated with a harness jack. Oppositely reciprocating knives engage the hooks when the latter are depressed to move the same outwardly to raise the corresponding harness frame. Said knives slide on the ways of the dobby and have a knife edge which engages the hooks.

In co-pending application Ser. No. 111,658 filed by Giles, there is shown a reversible dobby knife having edges'on diagonally op.- posite sides of the knife, the latter being of. parallelogrammatic cross section. With the dobby knife so constructed the strain of pulling the hooks comes on a part of the knife which is a relatively long distance from the axis thereof, and it is found that the knife turns on its gudgeons, causing the guide blocks to wear on the ways. In order to overcome this defect many single edge dobby knives at the present time have the hook engaging edge almost in alignment with the axis of the knife so as to reduce the turning moment to a minimum. it is a further object of my invention to provide a reversible dobby knife, having two edges, each lying very close to the axis of the knife to savewearing of the guide blocks. 7

In single edge knives where the strain of pulling the hooks comes close to the axis of the knife it is found necessary to strengthen the knife by casting an integral depending flange, there being no room to extend the same rearwardly because of interference with other parts of the dobby. It is a more particular object of my invention to provide a reversible knife having a cross sectional area substantially equal to that of the single knife, but without extending the same either downwardly or inwardly, the reinforced portion of the knife extending outwardly and lying on both sides of the axis of the rressnoncsnrrs, nssl enon ro.- oisorerron or woncns'rne, nasseonnsnrrs, A Corwenerron or non ooirnosnrns.

1923, Serial No. 112,148;

gudgeons, said parts preferably being joined by a reinforcing web.

With these and other objects in view which will appear as the description pro coeds, my invention resides in the combination and arrangement of parts hereinafter described and set forth in the claims.

In the accompanying drawings wherein I have showna convenient embodiment of my invention,

Fig. 1 is a front elevation of a portion of the dobby, parts being insection, having my invention applied thereto,

2 an enlarged top plan View of my improved knife looking in the direction of arrow 2, Fig. 1, the actuating links being shown in section, i

F ig. 8 is an enlarged vertical sect-ion on line of Fig. 2, showing the ways of the dobby which guide the knife blocks,

Fig. 4 is a perspective view ofthe knife, and

Fig". 5 is a detail diagrammatic in section, indicating the relation of my improved knife to certain operating parts of the dobby.

Referring particularly to Figs. 1 and 5, it will be seen that I have provided a loomsidc 10, having arches 11., and a dobby stand 12, to which are secured front and back dobby plates or sides 13 and 14, respectively. A rocker arm 15, having upper and lower knife engaging links 16 and 1'7, respectively, is pivoted as at- 18 on each side of the dobby. One of said arms has connection with the vertically reciprocating rod 19, driven by any appropriate part of the loom (not shown), to give the arms 15 an oscilla"ng movement every pick of the loom.

The pattern cylinder 20 having a pattern chain 21 rotates about a fixed center and controls the vertical position of dobby fin ,Q'ers '22, which are arranged in pairs as indicated in Fig. 5, oneset of fingers controlling the lower "hooks 23, and the other set of fingers controlling the upper hooks 24 by means of lifter rods 25. Said hooks are connected to the opposite ends of dobby back levers "216 each'of which pivoted as at 27' to a harnessjack 28. It isto be understood that the dobby is equipped with a number of back levers 26 and jacks 28 and that the View, partly iii) Cir

latter are attached by connections not shown to harness frames. As the jacks are moved to the right, as shown in Fig. 1 the corresponding harness frames will be raised, said movement being accomplished by having one or another of the hooks moved outwardly. The matter thus far described is of common construction and forms no part of my invention.

In carrying outmy improvements I provide a two edged dobby knife K, substantially as set forth in Figs. 2, 3, and 4, said knife having the usual aligned gudgeons 40, which receive the links 16 and 17, depending upon whether the knife is in upper or lower position. There will be two knives as indicated in Fig. 5, one for each set of hooks, and a description of one knife will suffice for both.

Adjacent to gudgeons are the usual guide blocks 41, which are so proportioned as to be received by the slots 42 formed in the dobby plates or sides and forming ways for said blocks. That portion of the knife which lies between the guide blocks 41 is particularly tne subyect matter of my 1nvention and comprises upper and lower hook engaging edges 43 and 44, as indicated more particularly in Fig. 3, the edge 48 being formed as the right hand upper terminus of a rearwardly extending portion 45, while the lower edge 44 is similarly formed as the left hand lower terminus of a portion 46. Said portions 45 and 46 are connected together by means'of a web 47 and the partsare so arranged as to lie symmetrically about the axis of the gudgeons 40.

When one edge has become worn sufficiently to be of no further use the knife may be disconnected from the links and reversed to present the other edge to the hooks. To facilitate grinding of the edges the guide blocks may be recessed as at 48.

From the foregoing it will be seen that I haveprovided a reversible dobby knife of substantial cross section but having the hook engaging edges very near the axis of the gudgeons so that the turning moment when lifting the harness frames will be a minimum. This effect is accomplished by extending a portion of the old type of knife forwardly and dispensing with the downwardly extending web heretofore used. The said web gave the desired strength but was in such position as to prevent the reversal of the knife, while the knife set forth herein retains the strength of the old construction and the feature of minimum twist coupled with reversibility.

Having thus described my invention it will be apparent that changes and modifications may be made therein by those skilled in the art without departing from the spirit and scope of the invention, and I do not wish to be limited to the details herein disclosed but what I claim is: r

1. A loom dobby knife having a pair of aligning gudgeons and having a pair of hook engaging knife edges symmetrically disposed with respect to the axis of the gudgeons, said knife having portions extending in opposite directions and transversely of the axis to points more distant from the axis than the knife edges.

2. A loom dobby knife having a pair of gudgeons and guiding blocks, said knife having a portion thereof extending between the guide blocks formed with a pair of knife edges symmetrically disposed with respect to and adjacent to the axis of the gudgeons, said knife having a pair of reinforcing portions extending laterally with respect to the knife edges and lying on the opposite sides of the axis of the gudgeons.

3. A reversible loom dobby knife, said knife having at each end thereof gudgeons and guide blocks, said gudgeons being substantially in alignment, the portion of the knife lying between the guide blocks being substantially horizontal and formed of a pair of portions lying on opposite sides of the axis of the gudgeons, each portion terminating near the center of the knife with a knife edge and having a reinforcing part extending away from the center of the knife.

4. A reversible loom dobby knife, said knife having ateach end thereof gudgeons and guide blocks, said gudgeons being substantially in alignment, the portion of the knife lying between the guide blocks being substantially horizontal and formed of a pair of portions lying on opposite sides of the axis of the gudgeons, each portion terminating near the center of the knife with a knife edge and having a reinforcing part extending away from the center of the knife, said portions being connected by a web lying between the knife edges.

5. A reversible loom dobby knife, said knife having at each end thereof gudgeons and guide blocks, said gudgeons being substantially in alignment, the portion of the knife lying between the guide blocks being substantially horizontal and formed of a pair of portions lying on opposite sides of he axis of the gudgeons, each portion terminating near the center of the knife with a knife edge and having a reinforcing part extending away from the center of the knife, said guide blocks being recessed near the knife edges for the purpose of guiding said edges.

In testimony whereof aflixed my signature.

WALTER n. WAKEFIELD.

I have hereunto 

